I remember this as an underwhelming text that was sustained by the usual MFA-ish platitudes ("write what ya know," "Kill your darlings," "Less is more," "Show, don't tell," "Find your voice," "Art comes from constraint," yada yada) and provided very little in terms of detailed instruction on technique nor did it venture into abstraction about the structure of narrative and properties of style.
Apart from some essays from high fliers, On Writing is largely comprised of excerpts from literary fiction pieces rather than writing about writing. Some of these excerpt are short fiction classics, but I'd characterize the lion's share of inclusion as representative of the kind of plotless, pointless, and precious fiction that is lapped up by the same literati that have functioned as the undertakers of humanistic and salient fiction.
It has been more than a decade since I've picked this one up so don't sue me if memory has forsaken me. Admittedly, at the time, I was neither well-read nor well-practiced enough to make any kind of writer myself. This book couldn't let me down then, though I'm somewhat confident it would now.